Patent Application
20230219323
The present disclosure generally relates to laminated films and, in particular, laminated films comprised of spiral cut and biaxially oriented films.
Plastic films are commonplace today and are used to create plastic bags, adhesive tapes, etc. Such plastic films include spiral-cut oriented (SC) films and biaxially oriented (BO) films.
In one aspect, a multi-laminate film comprises a first biaxially oriented film having a first machine direction angle. A first spiral cut oriented film has a second machine direction angle different than the first machine direction angle. The multi-laminate film also comprises at least one of a second biaxially oriented film having the first machine direction angle or a second spiral cut oriented film. The first biaxially oriented film, the first spiral cut oriented film and the at least one of the second biaxially oriented film or second spiral cut oriented film are laminated together.
In another aspect, a multi-laminate film comprises a plurality of films laminated together. Each film has a machine direction angle. The machine direction angles of at least two films of the plurality of films are different from each other.
Other objects and features of the present disclosure will be in part apparent and in part pointed out herein.
Corresponding reference characters indicate corresponding parts throughout the drawings.
The films disclosed according to this disclosure are multi-laminate films made from multiple films (e.g., plies) laminated or joined together. Each ply of film is preferably one of either a spiral-cut oriented film (SC film) or a biaxially oriented film (BO film). BO film refers to film that is oriented in two directions, the machine direction (e.g., generally parallel to the longitudinal axis LA of the film) and the cross machine direction. That is, after extrusion, the film is stretched in both the machine direction and the cross machine direction. As a reference point, BO film has a machine direction angle of about 0° (e.g., the machine direction angle is parallel to the machine direction or longitudinal axis LA of the film). SC film refers to film that is oriented in a direction other than the machine direction or cross machine direction (e.g., at an angle to the longitudinal axis LA of the film). That is, after extrusion, the direction the film was stretched in or has been oriented at an angle to the longitudinal axis LA of the film. Relative to BO films, the SC films have machine direction angles other than 0° such as +45° (relative to 0°) or −45° (relative to 0°). Preferably, the SC films have a machine direction angle between the inclusive range of about 30° to about 60° (e.g., a range of about 30° to 60° relative to 0° or about −30° to −60° relative to 0°). It is understood the SC films disclosed herein can have any machine direction angle between the inclusive range of about 30° to about 60°. The use of films of other orientations and orientations types are within the scope of the present disclosure.
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In one embodiment, the multi-laminate film may include more than three layers, and alternate between layers of SC films 10B and BO films 10A. In another embodiment, the multi-laminate films may alternate between layers of SC films 10B having different machine angles. For example, two SC films 10B can be adjacent to one another as long as they have different machine angles and, preferably, machine angles that are the opposite (e.g., positive and negative) of one another, such as +45° and −45°.
Using the principles outlined herein, it is possible to come up with any number of different permutations of SC and BO films 10B, 10A to form a multi-laminate film. Some of these different permutations are listed below in Table 1 (all BO films 10A have a machine orientation angle of 0°). The order of the individual films 10 in the multi-laminate film is given from left to right (e.g., upper most film to lower most film).
These different permutations of multi-laminate films are exemplary only, and other permutations are within the scope of the present disclosure. Accordingly, the multi-laminate films of the present disclosure generally (and broadly) includes a plurality of films 10 laminated together (e.g., one on top of another and so on). Each film 10 has a machine direction angle α. The machine direction angles α of at least two films 10 of the plurality of films are different from each other in the multi-laminate films of the present disclosure. Preferably, the films 10 are arranged such that no two adjacent films of the plurality of films have the same machine direction angle α (e.g., one film has a machine direction angle that is different than the machine direction angle of a film immediately above said one film and that is different than the machine direction angle of a film immediately above said one film). Desirably, each film 10 of the plurality of films is either a biaxially oriented film 10A or a spiral cut oriented film 10B. The multi-laminate film can include one or more (e.g., at least two) biaxially oriented films 10A. For example, the multi-laminate film can include one, two, three, four, five, etc. biaxially oriented films 10A. Likewise, the multi-laminate film can include one or more (e.g., at least two) spiral cut oriented films 10B. For example, the multi-laminate film can include one, two, three, four, five, six, seven, eight, etc. spiral cut oriented films 10B. Where the multi-laminate film includes multiple spiral cut oriented films 10B, the machine directions angles α for the spiral cut oriented films can all be the same, can all be different, or some of the machine directions angles can be the same. In one embodiment, the films 10 in the multi-laminate film are arranged to alternate between biaxially and spiral cut oriented films 10A, 10B (e.g., biaxially oriented film, spiral cut oriented film, biaxially oriented film, spiral cut oriented film and so on (depending on the total number of films)).
The multi-laminate film can be of generally any thickness. For example, a three film multi-laminate film 100 as shown in
Multi-laminate films of the present disclosure possess superior mechanical (e.g., strength) properties over conventional multi-laminate films. It is believed the layering of films 10 with different machine angles strengthens the multi-laminate film. Also, the multi-laminate films of the present disclosure experience little to no twist curling. The presence of multiple layered films 10 of different machine angles is believed to resist or counteract the internal forces within the multi-laminate film that can cause twist curling.
In one example, a multi-laminate film of the present disclosure was prepared and tested for mechanical properties in comparison to a corresponding commercially available prior art film. The multi-laminate film of the present disclosure tested was similar to the multi-laminate film 100 shown in
In additional examples, three multi-laminate films constructed according to the teachings of the present disclosure of different thicknesses were prepared and tested for mechanical properties in comparison to corresponding commercially available prior art films of comparable thicknesses. The multi-laminate films of the present disclosure tested were the same as shown in
For the following tables, the column heading “3 plies (2BE+SC)” is a multi-laminate film according to the present disclosure (this column has a light gray background), the column heading “2 plies” is a prior art film having two SC film layers and the column heading “4 plies” is a prior art film having four SC film layers. “BE” stands for a BO film 10A.
Table 2, below, shows the test results for a multi-laminate film with a thickness of 3 mils in comparison with corresponding prior art films of similar thicknesses. In this example, the SC film had a machine direction angle of +57.6°.
Table 3, below, shows the test results for a multi-laminate film with a thickness of 3.5 mils in comparison with corresponding prior art films of similar thicknesses. In this example, the SC film had a machine direction angle of +57.6°.
Table 4, below, shows the test results for a multi-laminate film with a thickness of 4 mils in comparison with corresponding prior art films of similar thicknesses. In this example, the SC film had a machine direction angle of 45.8°.
The results show that the multi-laminate films of the present disclosure have superior mechanical properties over the commercially available prior art films of similar thicknesses. As can be seen, the multi-laminate films of the present disclosure possessed greater tensile strengths than the prior art films and have less elongation. The multi-laminate films of the present disclosure also can withstand a greater impact than the prior art films. The multi-laminate films of the present disclosure also do not twist cure, unlike the prior art films having only two layers of SC film. The tests for the different mechanical properties were conducted under the appropriate ASTM standard as indicated in the tables above.
In additional examples, four multi-laminate films of the present disclosure of different thicknesses and different film arrangements were prepared and tested for mechanical properties. Film 1 (Item Number RXVT202-1) comprised two layers of BO film 10A with a SC film 10B therebetween (e.g., a multi-laminate film 100 as show in
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The physical properties of films 1-4 can be compared to the commercially available prior art films described in Tables 2-4. As can be seen, the results again show that the multi-laminate films of the present disclosure have superior mechanical properties over the commercially available prior art films of similar thicknesses (e.g., comparing the 2.7 mil thick Film 1 to the 3 mil thick prior art films of Table 2). As can be seen, the multi-laminate films of the present disclosure possessed greater tensile strengths than the prior art films and have less elongation. The multi-laminate films of the present disclosure also can withstand a greater impact than the prior art films. The tests for the different mechanical properties of films were conducted under the appropriate ASTM standard as indicated in the table above.
As used herein, terms of degree such as “about” and “generally” mean plus or minus 10%. For example, about 30 degrees means 30 degrees plus or minus 3 degrees (e.g., 27-33 degrees).
When introducing elements of the present disclosure or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
In view of the above, it will be seen that the several objects of the disclosure are achieved and other advantageous results attained.
As various changes could be made in the above products and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.
The present application is a continuation of U.S. application Ser. No. 17/332,630, filed May 27, 2021, which claims priority to U.S. Provisional Application No. 63/032,005, filed May 29, 2020, the entireties of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63032005 | May 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17332630 | May 2021 | US |
| Child | 18172967 | US |
